Which line from paragraph 4 provides a clue to the meaning of the word constricted? "Amazingly, the benefit of the laughter was similar to that of aerobic exercise
"Laughter apparently causes the endothelium to expand in order to increase blood flow."
"This supports earlier scientific findings, which indicated that mental stress causes blood vessels
to narrow."
"Research has established that mental stress is associated with damage to the endothelium, the
protective barrier lining our blood vessels,

Which sentence is punctuated correctly?  a.under a microscope; the organisms look a bit like ruffled tennis balls they have armored plates that fit together to make a round shape. b.when the water is disturbed; the organisms respond by glowing this makes swimmers look like floating beams of blue light. c.there is a bay in puerto rico that seems to light up at night; the light comes from tiny organisms in the water. d.the luminescence attracts visitors from around the world people are curious to see; this beautiful otherworldly sight.